diff --git a/tools/singularity/ubuntu18.04.def b/tools/singularity/ubuntu18.04.def
index 93cc4e8939..bfc598b157 100644
--- a/tools/singularity/ubuntu18.04.def
+++ b/tools/singularity/ubuntu18.04.def
@@ -3,6 +3,8 @@ From: ubuntu:18.04
 
 %post
     export DEBIAN_FRONTEND=noninteractive
+    apt-get update
+    apt-get install --no-install-recommends -y software-properties-common
     add-apt-repository ppa:openkim/latest
     apt-get update
     apt-get upgrade --no-install-recommends -y
diff --git a/tools/singularity/ubuntu20.04.def b/tools/singularity/ubuntu20.04.def
index cbc691b4b7..ed7a67bbe0 100644
--- a/tools/singularity/ubuntu20.04.def
+++ b/tools/singularity/ubuntu20.04.def
@@ -3,6 +3,8 @@ From: ubuntu:20.04
 
 %post
     export DEBIAN_FRONTEND=noninteractive
+    apt-get update
+    apt-get install --no-install-recommends -y software-properties-common
     add-apt-repository ppa:openkim/latest
     apt-get update
     apt-get upgrade --no-install-recommends -y